1. Field of the Invention
The present invention relates to a power divider, more particularly to a power divider with a microstrip structure.
2. Description of the Related Art
Referring to FIG. 1, a conventional one input to four output power divider 1 is composed of three one input to two output wired transformers 11, 12 and 13, and a plurality of resistors (not shown). However, adopting a structure using the wired transformers has some defects. First of all, the wired transformer has a higher component cost. Secondly, pins of the wired transformer are required to be arranged manually for subsequent soldering, such that only manual soldering may be adopted and SMT (Surface Mount Technology) soldering may not be utilized, resulting in longer working hours to solder the wired transformer. Thirdly, since the wired transformers are soldered manually, characteristics of the power divider may deviate as a result of differences in soldering among individuals.
Therefore, for the purpose of reducing cost, working hours for soldering and deviation in characteristics of the power divider, a conventional power divider with a microstrip structure designed based on a microstrip power divider is provided. Referring to FIG. 2, a conventional one input to four output power divider 2 includes three sets of single-stage one input to two output microstrip power dividers 21, 22 and 23. However, it is apparent from the S-parameters of the one input to four output power divider 2 illustrated in a simulation thereof in FIG. 3 that the reflection coefficients S(1, 1) of the one input to four output power divider 2 at 50 MHz and 700 MHz are poor, resulting in an insufficient working bandwidth. Therefore, the conventional one input to four output power divider is not suited to operate in a working frequency band ranging from 50 MHz to 806 MHz.